Device having a light transmission device

ABSTRACT

The invention provides a device having a light transmission device wherein a light-emitting element, a driving circuit for driving this light-emitting element, a light-receiving element (light-detecting element), a light-guiding path (wave-guiding path) for guiding light from the light-emitting element to the light-receiving element, an amplifying circuit, wiring and a circuit are successively provided on a substrate. The light from the light-emitting element passes through the light-guiding path and is received at the light-receiving element, transferring photoelectricity. The electric signals from the light-receiving element are amplified at the amplifying circuit and are input to the circuit through the wiring. The circuit operates based on these electric signals.

TECHNICAL FIELD

[0001] The present invention relates to a device having a lighttransmission means.

PRIOR ART TECHNOLOGY

[0002] Conventional semiconductor devices (such as, for instance, liquidcrystal display elements having TFT elements) connect predeterminedelements to elements through electric wiring, and drive circuits bytransmitting information only with electric signals.

[0003] However, in the conventional devices, there is a problem in thatsignals are delayed due to the capacity and the wiring resistance ofelectric wiring (wiring). As semiconductor devices become denser, thissignal delay becomes longer, which is a large obstacle to theacceleration of semiconductor devices. There is also the problem ofheating due to wiring resistance. Although an information transmissionmeans by light using optical fiber is known, the applications thereofare limited to relatively large devices.

SUMMARY OF THE INVENTION

[0004] It is an object of the present invention to provide a devicehaving a light transmission means that is different from an informationtransmission method using electric signals, particularly, a devicehaving a light transmission means that can improve integration andspeed.

[0005] In order to solve these problems, the present invention providesthe device described in the (1) to (21) hereafter. (1) A device having alight transmission means includes the light transmission means wherein alight-emitting section having at least one light-emitting element madeof a thin film, a light-receiving section having at least onelight-receiving element made of a thin film, and a light-guiding paththat guides light from the light-emitting section to the light-receivingsection are integrated. (2) According to the device described in (1),the light-emitting section, the light-receiving section and thelight-guiding path are arranged in at least a one-dimensional direction.(3) According to the device described in (1) or (2), the light-emittingsection, the light-receiving section and the light-guiding path arearranged on the same substrate. (4) According to the device described in(1), the light-emitting section, the light-receiving section and thelight guiding path are arranged in a two-dimensional direction. (5)According to the device described in (1), the light-emitting section,the light-receiving section and the light-guiding path are arranged in athree-dimensional direction. (6) According to the device described in(5), a layer having at least one of the light-emitting section, thelight-receiving section and the light-guiding path is laminated. (7)According to the device described in any of (1) to (6), thelight-emitting section has a plurality of light-emitting elements withdifferent light-emitting characteristics. (8) According to the devicedescribed in any of (1) to (6), the light-emitting section has aplurality of light-emitting elements with different peak wavelengths ofemitted light. (9) According to the device described in (7) or (8), thelight-receiving section has a plurality of light-receiving elements thatreceive light from the corresponding light-emitting elements. (10)According to the device described in any of (1) to (9), at least onethin film constituting the light-emitting element is patterned by an inkjet method. (11) According to the device described in any of (1) to(10), the light-emitting element is composed of an organic EL element.(12) According to the device described in any of (1) to (10), thelight-emitting element is composed of an organic EL element and anoptical filter. (13) According to the device described in (12), theoptical filter is a distributed reflection multilayer film mirror madeof a plurality of laminated thin films having different refractiveindexes. (14) According to the device described in any of (1) to (13),at least one thin film composing the light-receiving element ispatterned by an ink jet method. (15) According to the device describedin any of(1) to (14), the light-receiving element is composed of anorganic element. (16) According to the device described in any of (1) to(14), the light-receiving element is composed of an organic element andan optical filter. (17) According to the device described in any of (1)to (16), the light-guiding path is composed of thin films. (18)According to the device described in any of (1) to (17), at least onethin film composing the light-guiding path is patterned by an ink jetmethod. (19) The device according to any of (1) to (18) has a thin filmtransistor. (20) The device according to any of (1) to (18) has aplurality of circuit blocks on the same substrate, wherein each of theplurality of circuit blocks has the light-emitting section and thelight-receiving section. (21) According to the device described in (20),a gap between predetermined circuit blocks of the plurality of circuitblocks is connected by the light-guiding path, wherein signals aretransmitted and received by light through the light-guiding path betweenthe circuit blocks.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is a type view, showing major sections of a device having alight transmission means of one embodiment of the present invention;

[0007]FIG. 2 is a cross-sectional view, showing a configuration of anorganic EL element used as a light-emitting element and a configurationof a light-guiding path in the present invention;

[0008]FIG. 3 is a view to explain a method of manufacturing organic ELelements by ink jet printing;

[0009]FIG. 4 is a cross-sectional view, showing a configuration of a PINphotodiode used as a light-receiving element and a configuration of alight-guiding path in the present invention;

[0010]FIG. 5 is a circuit view, showing a configuration of an amplifyingcircuit in the present invention;

[0011]FIG. 6 is a circuit view, showing another configuration of anamplifying circuit in the present invention;

[0012]FIG. 7 is a block view, showing another configuration of anamplifying circuit in the present invention;

[0013]FIG. 8 is a circuit view, showing a configuration of a currentamplifier in the present invention;

[0014]FIG. 9 is a type view, showing major sections of a device having alight transmission means of another embodiment of the present invention;

[0015]FIG. 10 is a cross-sectional view, showing a configuration of alight-emitting element and a light-guiding path in the presentinvention;

[0016]FIG. 11 is a cross-sectional view, showing a configuration of alight-emitting element and a light-guiding path in the presentinvention;

[0017]FIG. 12 is a cross-sectional view, taken along the line A-A inFIG. 11;

[0018]FIG. 13 is a type view, showing major sections of a device havinga light transmission means of another embodiment of the presentinvention; and

[0019]FIG. 14 is a type view, showing major sections of a device havinga light transmission means of another embodiment of the presentinvention.

BEST MODES FOR CARRYING OUT THE INVENTION

[0020] A device having a light transmission means of the presentinvention is explained hereafter, below in detail based on the preferredembodiments shown in the attached figures.

[0021]FIG. 1 is a type view, showing major sections of a device having alight transmission means of one embodiment of the present invention.

[0022] A device (semiconductor device) 1 shown in the figure has asubstrate 2. Placed on this substrate 2 are a light-emitting element 3,a circuit (a circuit on the transmission side) that has a drivingcircuit 3 not shown in the figure for driving this light-emittingelement 3 and that sends signals to the light-emitting element 3, alight-receiving element (light-detecting element) 5, a light-guidingpath (wave-guiding path) 4 for guiding the light from the light-emittingelement 3 to the light-receiving element 5, an amplifying circuit 6, awiring (electric wiring) 7, and a circuit 8.

[0023] Specifically, integrated on the substrate 2 are thelight-emitting element 3, each element and the wiring thereofconstituting the circuit that has the driving circuit and sends signals,the light-guiding path 4, the light-receiving element 5, each elementand the wiring thereof constituting the amplifying circuit 6, the wiring7, and each element and the wiring thereof constituting the circuit 8.

[0024] Materials for the substrate 2 include, for instance, variousglasses, Si monocrystals, ceramics, quartz and so forth.

[0025] Moreover, each of the light-emitting element 3, the light-guidingpath 4 and the light-receiving element 5 are partially or totally madeof a thin film.

[0026] The light-emitting section is constituted of the light-emittingelement 3; the light-receiving section is formed of the light-receivingelement 5; and the light transmission means is made up of thelight-emitting element 3, the light-guiding path 4 and the lightreceiving element 5.

[0027] For instance, an organic EL element can be used as thelight-emitting element 3 in this device 1. As the light-receivingelement 5, a photodiode or the like may be used.

[0028]FIG. 2 is a cross-sectional view, showing a configuration of anorganic EL element used as the light-emitting element 3 and aconfiguration of the light-guiding path 4.

[0029] As shown in the figure, the organic EL element 3 a is constitutedof a transparent electrode 31, a light-emitting layer (organic EL layer)32, a metal electrode 33 and banks 34 used as shielding sections as wellas walls for preventing the ink from spreading. This organic EL element3 a is placed on a light-guide path 4, which is explained below. Theconfiguration of the organic EL element 3 a will be explained below indetail.

[0030] The banks 34 are formed on the SiO₂ layer 43 of the light-guidingpath 4 described below. Each of the transparent electrode 31 and thelight-emitting layer 32 is formed on the inner side of the banks 34. Inthis case, the transparent electrode 31 is formed on the SiO₂ layer 43,and the light-emitting layer 32 is formed on the transparent electrode31. Moreover, the metal electrode 33 is formed on the banks 34 and thelight-emitting layer 32.

[0031] The transparent electrode 31 is made of, for instance, ITO or thelike. Moreover, the thickness of the transparent electrode 31 ispreferably about 50 to 500 nm.

[0032] For the light-emitting layer 32, organic light-emitting materialsare applied as a light-emitting material. In this case, the flexibilityin selecting light-emitting wavelengths is significant; indeed, variouswavelengths can be selected by selecting particular materials or bymixing materials.

[0033] As organic light-emitting material, a material is selectedwherein the energy of excitation in the light-emitting material isequivalent to the energy difference between the HOMO (highest occupiedlevel) and the LUMO (lowest unoccupied level) corresponding to theforbidden bandwidth of the organic material. For example, low molecules,macromolecules, conjugate macromolecules with conjugate developmentparticularly at principal chains, conductive macromolecules and pigmentmolecules are chosen.

[0034] When low-molecular organic materials are used as the organiclight-emitting material, anthracene, PPCP, Zn (OxZ)₂, disutyl benzene(DSB), the derivatives thereof (PESB), and so forth are used to emit,for instance, blue light. Additionally, in order to emit e.g., greenlight, Alq₃, coronene, and so forth are used. Moreover, BPPC, perylene,DCM, and the like are applied to emit e.g., red light.

[0035] Also, when high-molecular organic light-emitting materials areapplied as organic light-emitting materials, applied are PAT and thelike to emit e.g., red light, MEH-PPV and so forth to emit orange light,PDAF, FP-PPP, RO-PPP, PPP or the like to emit blue light, and PMPS orthe like to emit purple light.

[0036] As other organic light-emitting materials, PPV, RO-PPV, CN-PPV,PdPhQx, PQx, PVK (poly (N-vinylcarvazol)), PPS, PNPS, PBPS, and the likeare applied.

[0037] Particularly, PVK can vary light-emitting wavelengths(luminescent colors) by controlling the mixed concentration and thedischarge frequency of dopant ink of pigment molecules having poorcarrier ability such as Eu complex. For instance, when a fluorescentpigment is doped into an organic light-emitting material comprising PVK,luminescent colors may be arranged. As the pigments of 1, 1, 4,4-tetraphenyl-1, 3,-butadiene (TPB), coumarin 6 and DCM1 are doped intoPVK, luminescent colors may be blue, green and orange, respectively.Moreover, when three types of pigments are doped to PVK at the sametime, a wide spectrum can be provided. If rhodamine B or DCM can bedoped into PPV, luminescent colors may be selectively varied from greento red.

[0038] Preferably, a composition for an organic EL element (acomposition for the light-emitting layer 32) is heated wherein mainlythe precursor of conjugate high-molecular organic compounds forming thelight-emitting layer 32 itself, or the precursor and fluorescentpigments or the like are dissolved or dispersed in a predeterminedsolvent so as to vary light-emitting characteristics of thelight-emitting layer 32. The precursor in the composition for theorganic EL element is formed in a polymerized thin film (solid thinfilm). Alternatively, as another example, the light-emitting layer 32 isformed of a high-molecular thin film by drying or heating a composition(a composition for the light-emitting layer 32) wherein conjugatemacromolecules themselves that are soluble in an organic solvent, or theconjugate macromolecules and fluorescent pigments or the like so as tovary light-emitting characteristics of the light-emitting layer 32 aredissolved. The thickness of the light-emitting layer 32 is preferablyabout 50 to 500 nm.

[0039] For the metal electrode 33, for instance, Al-Li or the like isapplied. Additionally, the thickness of the metal electrode 33 ispreferably about 10 to 500 nm.

[0040] For the banks 34, for example, polyimide, SiO₂, or the like isused. Moreover, the bank 34 is preferably thicker than the totalthickness of the transparent electrode 31 and the light-emitting layer32.

[0041] As mentioned above, on the substrate 2 shown in FIG. 1, thecircuit on the transmission side is provided that has a driving circuitnot shown in the figure for driving the organic EL element 3 a.Moreover, when a predetermined voltage is applied between thetransparent electrode 31 and the metal electrode 33 from the drivingcircuit at this organic EL element 3 a, electrons and holes are injectedinto the light-emitting layer 32. They shift inside the light-emittinglayer 32 due to the increased power by applied voltage, and arerecombined. Excitation occurs due to this recombination, and releasesenergy (fluorescence and phosphorescence) when it returns to a basestate. In other words, light is emitted. Such a phenomenon is called ELemission.

[0042] The method of manufacturing the organic EL element 3 a will nowbe explained. In this embodiment, the organic EL element 3 a having theconfiguration shown in FIG. 2 is manufactured by ink jet printing.

[0043] This manufacturing method by ink jet printing is a method ofdischarging (ejecting) a predetermined composition (a dischargesolution) from a head, patterning a predetermined thin film (layer)material and solidifying it into a thin film in the ink jet method. Themethod of manufacturing the organic EL element 3 a by ink jet printingis explained in detail hereafter, with reference to FIG. 3.

[0044] As shown in the figure, first, the banks 34 are formed, forinstance, by photolithography. Then, the composition for the transparentelectrode 31 prepared in advance is formed in a pattern on thelight-guiding path 4 by the ink jet method. Specifically, thecomposition for the transparent electrode 31 is ejected from a nozzle 90of a head for ink jet, thus forming predetermined patterns. Then, thepatterned composition for the transparent electrode 31 is heated andsolidified, thereby forming the transparent electrode 31.

[0045] Subsequently, the composition for the light-emitting layer 31prepared in advance is patterned by the ink jet method. Specifically,the composition for the light-emitting layer 32 is discharged from anozzle 100 of a head for ink jet, thus forming a predetermined pattern.Then, a layer 320 of the composition for this patterned light-emittinglayer 32 is heated, and the precursor of a conjugate high-molecularorganic compound in the layer 320 is polymerized. In other words, thelayer 320 is solidified, thus forming the light-emitting layer 32.

[0046] Finally, the electrode 33 is formed by, for instance, asputtering or deposition method, thus providing the organic EL element 3a having the configuration shown in FIG. 2.

[0047] According to the ink jet printing, in other words, the ink jetmethod, fine patterning may be easily, quickly and precisely carriedout, so that light-emitting properties such as the conditions, coloringbalance and brightness can be easily and freely controlled.

[0048] Therefore, the organic EL element 3 a having preferablecharacteristics, size and patterns can be easily formed on the substrate2 where particularly fine elements such as TFT (thin film transistor)circuits or general monocrystal Si base ICs are integrated.

[0049] The light-guiding path 4 having the configuration shown in FIG. 2is constituted of an Si0 ₂ layer 41, an Si0 ₂ layer 43, and an ITO layer42 provided between the Si0 ₂ layer 41 and Si0 ₂ layer 43. In this case,the Si0 ₂ layer 41 is formed on the substrate 2. The thickness of theSiO₂ layer 41 is preferably about 50 nm to 10 μm. The thickness of theITO layer 42 is preferably about 30 nm to 10 μm. The thickness of theSi0 ₂ layer 43 is preferably about 50 nm to 10 μm.

[0050] As shown in FIG. 1, this light-guiding path 4 extends at leastfrom the organic EL element 3 a (light-emitting element 3) to a PINphotodiode 5 a (light-receiving element 5), explained hereafter, andguides the light from the organic EL element 3 a to the PIN photodiode 5a.

[0051] The light-guiding path 4 can be manufactured by conventionalmethods of forming thin films (CVD, PVD and the like) andphotolithography.

[0052] Furthermore, the light-guiding path 4 may also be manufactured byink jet printing as the organic EL element 3 a mentioned above.Specifically, at least one thin film (layer) constituting thelight-guiding path 4 is manufactured by patterning a predeterminedcomposition in the ink jet method and then solidifying it, as theorganic EL element 3 a mentioned above. In this case, theabove-described effects by ink jet printing can be obtained.

[0053] On the other hand, as the light-receiving element 5 having theconfiguration shown in FIG. 1, for instance, a PIN photodiode may beused.

[0054]FIG. 4 is a cross-sectional view, showing the configuration of thePIN photodiode used as the light-receiving element 5 and a configurationof the light-guiding path 4.

[0055] As shown in the figure, the PIN photodiode 5 a is formed of alight-receiving window electrode 51, a p-type a-SiC layer (p-typesemiconductor layer) 52, an i-type a-Si layer (semiconductor layer) 53,an n-type a-SiC layer (n-type semiconductor layer) 54, and an Al-Si-Culayer 55 used as a light-receiving top electrode as well as wiring(electric wiring).

[0056] These light-receiving window electrode 51, p-type a-SiC layer 52,i-type a-Si layer 53, n-type a-SiC layer 54, and Al-Si-Cu layer 55 arelaminated successively from the bottom in FIG. 4.

[0057] This PIN photodiode Sa is provided on the light-guiding path 4 soas to make the light-receiving window electrode 51 face the ITO layer 42of the light-guiding path described above. Additionally, the Si0 ₂ layer43 is not formed at the section corresponding to the light-receivingwindow electrode 51 of the light-guiding path 4.

[0058] The light-receiving window electrode 51 is formed of, forexample, ITO or the like. The thickness of this light-receiving windowelectrode 51 is preferably about 50 nm to 1 μm.

[0059] Moreover, as an example, the thickness of the p-type a-SiC layer52, the i-type a-Si layer 53, the n-type a-SiC layer 54 and the Al-Si-Culayer 55 is 50 nm, 80 nm, 50 nm and 1 μm, respectively.

[0060] However, the above-mentioned thickness of each layer is notlimited to the value mentioned above. Specifically, the thickness ofeach layer is significantly variable. The thickness of each layer isflexible.

[0061] This PIN photodiode 5 a may be manufactured by ink jet printingas the organic EL element 3 a described above. Specifically, at leastone thin film (layer) constituting the PIN photodiode 5 a can bemanufactured by patterning a predetermined composition in the ink jetmethod and solidifying it, as the above-described organic EL element 3a. In this case, the above-mentioned effects by ink jet printing can beprovided.

[0062] Also, in the present invention, organic photo detective materials(organic elements) may be applied in addition to the PIN photodiode 5 amentioned above. As these organic photo detective materials, forexample, the same material as the above-described organic EL element 3 amay be used. For example, a mixture of PPV and cyano-PPV, or the likemay be used.

[0063] As shown in FIG. 1, to the PIN photodiode 5 a mentioned above, aninput side of the amplifying circuit 6 is connected.

[0064] The amplifying circuit 6 includes, for instance, a CMOS typedigital amplifying circuit 61 having a P-channel and an N-channelMOS-FET (field effect transistor) shown in FIG. 5, a Bi-CMOS typedigital amplifying circuit 62 having a bipolar transistor and an MOS-FETshown in FIG. 6, and an amplifying circuit 63 constituted of a currentamplifier (analog amplifying circuit) 631 shown in FIG. 7 and FIG. 8 andan A/D converter 632, and so forth.

[0065] Additionally, in the case of the amplifying circuit 63, electricsignals (analog signals) are input to the current amplifier 631, and areinput to the A/D converter 63 after the current values (signal level)thereof are amplified. Subsequently, these amplified signals areconverted from analog signals to digital signals by the A/D converter632, and are output.

[0066] On the other hand, as shown in FIG. 1, to the output side of theabove-described amplifying circuit 6, is connected the predeterminedcircuit 8 through the wiring 7. The circuit 8 includes, for instance, acircuit having an FET (field effect transistor) formed on an Simonocrystal, and a circuit having a TFT (thin film transistor), and thelike. The operation of the device 1 will now be explained.

[0067] As described above, at the circuit on the transmission side notshown in FIG. 1, the transmitted (generated) electric signals are inputinto the driving circuit, and the driving circuit drives the organic ELelement 3 a (light-emitting element 3) based on the electric signals andemits light. Accordingly, light signals (light) are generated. In otherwords, the organic EL element 3 a is driven by the driving circuit,converting the electric signals into light signals (light) and sending(transmitting) them.

[0068] In this case, as shown in FIG. 2, the light from thelight-emitting layer 32 of the organic EL element 3 a transmits thetransparent electrode 31 and the SiO₂ layer 43 as shown in the arrows inFIG. 2, and then enters the ITO layer 42. Subsequently, the light isrepeatedly reflected at an interface between the SiO₂ layer 41 and theITO layer 42 and an interface between the SiO₂ layer 43 and the ITOlayer 42, and travels inside the ITO layer 42 toward the PIN photodiode5 a (light-emitting element 5).

[0069] As illustrated in FIG. 4, the light from the organic EL element 3a enters from the light-emitting window electrode 51 as shown in thearrows in FIG. 4. In other words, the light is received at the PINphotodiode 5 a.

[0070] Subsequently, from the PIN photodiode 5 a, the electric currentcorresponding to the quantity of received light, in other words,electric signals (signals) are output. (Light signals are converted intoelectric signals and then output.) The signals from the PIN photodiode 5a are amplified at the amplifying circuit 6, and are input to thecircuit 8 through the wiring 7. The circuit 8 operates based on thesesignals.

[0071] As explained above, according to this device 1, information(signals) are transmitted mainly by optical communication in the device1 wherein fine elements are integrated, thus preventing heating causedby the resistance of electric wiring between the organic EL element 3 aand the PIN photodiode 5 a. Accordingly, the heating from the device 1can be reduced.

[0072] Moreover, since there is no signal delay between the organic ELelement 3 a and the PIN photodiode 5 a, a device (circuit) with goodresponse properties can be provided.

[0073] Moreover, if the organic EL element 3 a, the light-guiding path4, the PIN photodiode 5 a, and the like are formed on the substrate 2 byink jet printing, the productivity of the device 1 improves, which isadvantageous to mass production.

[0074] Now, the device having a light transmission means of anotherembodiment of the present invention will be explained. In the device(semiconductor device) shown in FIG. 9, a light-emitting section iscomposed of a plurality (three in this embodiment) of light-emittingelements 30 having different light-emitting characteristics (peakwavelengths of emitting light in this embodiment), and thelight-receiving section is made up of a plurality (three in thisembodiment) of light-receiving elements 50 receiving light from thecorresponding light-emitting elements 30. Due to this configuration, aplurality (three kinds in this embodiment) of information (signals) maybe transmitted at the same time by using the same light-guiding path 4.The device 10 is explained hereafter, in detail.

[0075] As shown in FIG. 9, the device 10 has a substrate 2. Provided onthis substrate 2 are a plurality (three in this embodiment) oflight-emitting elements 30, driving circuits for driving eachlight-emitting element 30 not shown in the figure, a plurality (three inthis embodiment) of light-receiving elements (photo detective elements)50, the light-guiding path (wave-guiding path) 4 that guides the lightfrom the light-emitting elements 30 to the light-receiving elements 50,a plurality (three in this embodiment) of amplifying circuits 60, aplurality (three in this embodiment) of wirings (electric wirings) 70,and a circuit 8.

[0076] Specifically, on the substrate 2, integrated are threelight-emitting elements 30, each element and the wiring thereofconstituting the driving circuits, the light-guiding path 4, threelight-receiving elements 50, each element and the wiring thereofconstituting three amplifying circuits 60, three wirings 70, and eachelement and the wiring thereof constituting the circuit 8.

[0077] Materials for the substrate 2 include, for example, variousglasses, Si monocrystals, ceramics, quartz, and the like.

[0078] Moreover, each of the light-emitting elements 30, thelight-guiding path 4 and the light-receiving element 50 are partially ortotally made of a thin film.

[0079] As described above, each light-emitting element 30 in this device10 has different peak wavelengths of emitting light. The peakwavelengths of the emitting light from the three light-emitting elements30 are supposed to be λ1, λ2 and λ3, respectively. It is preferable thatthese λ1, λ2 and λ3 are separated from each other to some degree so asto selectively receive light on the side of the light-receiving elements50.

[0080] Each light-emitting element 30 in this device 10 may be formed bychanging the materials and compositions of the organic EL layer(light-emitting layer 32) or changing filter characteristics.

[0081]FIG. 10 is a cross-sectional view, showing a configuration oflight-emitting elements 30 and a configuration of a light-guiding path4. As illustrated in the figure, each light-emitting element 30 is madeup of an organic EL element 3 a that is formed of a light-emitting layer(organic EL layer) 32, a metal electrode 33 and a bank 34 used as ashielding section as well as a wall to prevent ink from spreading, andan optical filter 35. Each light-emitting element 30 is provided on thelight-guiding path described later.

[0082] The configuration of the light-emitting element 30 is explainedin detail hereafter. Banks 34 are formed on the SiO₂ layer 43 of thelight-guiding path 4 described hereafter.

[0083] Additionally, each transparent electrode 31, light-emitting layer32 and optical filter 35 are formed inside banks 34. In this case, anoptical filter 35 is formed on the SiO₂ layer 43; a transparentelectrode 31 is formed on the optical filter 35; and a light-emittinglayer 32 is formed on the transparent electrode 31.

[0084] Subsequently, the metal electrode 33 is formed on the banks 34and the light-emitting layers 32. This metal electrode is a commonelectrode for each organic EL element 3 a.

[0085] The light-emitting layers 32 will now be described. By usingorganic light-emitting materials as light-emitting material, theflexibility in selecting light-emitting wavelengths is large; indeed,the choice of various wavelengths is possible by selecting particularmaterials and mixing materials. As organic light-emitting materials, amaterial is selected wherein the energy of excitation in thelight-emitting material is equivalent to an energy difference betweenHOMO (highest occupied level) and LUMO (lowest unoccupied level)corresponding to the forbidden bandwidth of the organic material. Forexample, low-molecules, macromolecules, conjugate macromolecules withconjugate development particularly at principal chains, conductivemacromolecules and pigment molecules are chosen. Specifically, it ispossible to appropriately select materials that were used as examplesfor the light-emitting layer 32 at the organic EL element 3 a having theconfiguration shown in FIG. 2, in response to desirable wavelengths.

[0086] Moreover, the wavelength (peak wavelength, wavelength band andthe like) of the light obtained from a light-emitting layer is alsoadjustable to some extent by the optical filter 35.

[0087] In case of emitting the light with a wide wavelength band (band)as white light and controlling the wavelength, a general absorption typeoptical color filter (color filter) can be used as the optical filter35, and only light with a preferable color (wavelength) may betransmitted thereby, thus generating light signals.

[0088] As the optical filter 35, for instance, there is a distributedreflection multilayer film mirror (DBR mirror). For example, the lightemitted from the organic EL element 3 a generally has a wavelength band(the width of a wavelength) of 100 nm or wider. However, when a DBRmirror is used as the optical filter 35, this wavelength may benarrow-banded. (The width of a wavelength may be narrowed).Additionally, if a plurality of DBR mirrors is used, a plurality oflights with different peak wavelengths and sharp peaks can be obtainedfrom the light having a wavelength band of e.g., about 100 nm.

[0089] Therefore, by changing the materials of the light-emitting layers32 of the organic EL elements 3 a, the peak wavelengths of eachlight-emitting element 30 can be set at λ1, λ2 and λ3, respectively.Also, by changing the optical filters 35, the peak wavelengths of eachlight-emitting element 30 may be set at λ1, λ2 and λ3, respectively.

[0090] However, it is preferable to set the peak wavelengths of eachlight-emitting element 30 at λ1, λ2 and λ3, respectively, by changingthe materials of the light-emitting layers 32 of the organic EL elements3 a and also by changing the optical filters 35.

[0091] The DBR mirror mentioned above is the lamination of a pluralityof thin films having different refractive indexes, particularly, themirror having a plurality of pairs comprising two kinds of thin filmswith different refractive indexes (the mirror which is periodicallylaminated).

[0092] The materials of the thin films for the DBR mirror include, forinstance, semiconductor materials, dielectric materials, and so forth.Among these, dielectric materials are preferable. They can be formed bya general vacuum film forming method. Moreover, the organic compoundsoluble in an organic solvent can be applied as a starting material forthe dielectric material, which is easily applicable to patterning in theabove-mentioned ink jet method.

[0093] The organic EL element 3 a of each light-emitting element 30 mayalso be manufactured by ink jet printing, as in the above-describedorganic EL element 3 a of the device 1. Specifically, at least one thinfilm (layer) constituting the organic EL element 3 a of eachlight-emitting element 30 may be manufactured by patterning apredetermined composition in the ink jet method and solidifying it, asthe above-mentioned organic EL element 3 a of the device 1. In thiscase, the effects by ink jet printing mentioned above can be obtained.

[0094] Additionally, thin films constituting the DBR mirror (opticalfilter 35) of each light-emitting element 30 may be formed by theliquid-phase film forming method.

[0095] The liquid-phase film forming method is a method in which a thinfilm material (coating solution) is a (liquid) composition having thecomponents of the thin film dissolved or dispersed in a solvent, and athin film is formed without evaporating the thin film material.

[0096] More preferably, each DBR mirror may be manufactured by ink jetprinting as with the above-mentioned organic EL element 3 a of thedevice 1. Specifically, each thin film constituting each DBR mirror canbe manufactured by patterning the composition mentioned above in the inkjet method and solidifying it as the above-noted organic EL element 3 aof the device 1. In this case, the above-described effects by ink jetprinting can be obtained.

[0097] As illustrated in FIG. 10, the light-guiding path 4 isconstituted of an i0 ₂ layer 41, an SiO₂ layer 43, and an ITO layer 42provided between the SiO₂ layer 41 and the SiO₂ layer 43. In this case,the SiO₂ layer 41 is formed on the substrate 2. The thicknesses of theSiO₂ layer 41, the ITO layer 42, and the SiO₂ layer 43 are the same asthose of the device 1 mentioned above.

[0098] As shown in FIG. 9, this light-guiding path 4 extends at leastfrom each light-emitting element 30 to each light-receiving element 50,and guides the light from each light-emitting element 30 to thecorresponding light-receiving element 50.

[0099] The light-guiding path 4 may also be manufactured using ink jetprinting as the organic EL element 3 a mentioned above. Specifically, atleast one thin film (layer) constituting the light-guiding path 4 ismanufactured by patterning a predetermined composition in the ink jetmethod and then solidifying it, as the organic EL element 3 a mentionedabove. In this case, the above-described effects by ink jet printing canbe obtained.

[0100] The light-receiving element 50 may be made up of, for instance, aPIN photodiode and a predetermined optical filter, and may also beconstituted of the same organic element and predetermined optical filteras those for the above-mentioned device 1.

[0101]FIG. 11 is a cross-sectional view, showing a configuration of thelight-receiving element 50 and the light-guiding path 4. FIG. 12 is across-sectional view, taken along the line A-A in FIG. 11.

[0102] As shown in the figure, each light-receiving element 50 is formedof a PIN photodiode 5 a, which is made up of a light-receiving windowelectrode 51, a p-type a-SiC layer (p-type semiconductor layer) 52, ani-type a-Si layer (semiconductor layer) 53, an n-type a-SiC layer(n-type semiconductor layer) 54 and an Al-Si-Cu layer 55 used as alight-receiving top electrode as well as wiring (electric wiring), andan optical filter 56.

[0103] These optical filter 56, light-receiving window electrode 51,p-type a-SiC layer 52, i-type a-Si layer 53, n-type a-SiC layer 54 andAl-Si-Cu layer 55 are laminated successively from the bottom in FIG. 11.In this case, the optical filters 56 are formed so as to cover thelight-receiving window electrodes 51.

[0104] Each light-receiving element 50 is provided on the light-guidingpath 4 so as to let the light-receiving window electrode 51 face the ITOlayer 42 of the light-guiding path 4 through the optical filter 56.Additionally, at the section corresponding to the light-receiving windowelectrode 51 of the light-guiding path 4, the SiO₂ layer 43 is notformed.

[0105] The material and the thickness of the light-receiving windowelectrode 51 are the same as those of the device 1 mentioned above.

[0106] Moreover, the thickness of the p-type a-SiC layer 52, the i-typea-Si layer 53, the n-type a-SiC layer 54 and the Al-Si-Cu layer 55 isalso the same as those of the device 1 mentioned above.

[0107] When the peak wavelengths of the light from the light-emittingelements 30 are λ1, λ2 and λ3 respectively, the optical characteristicsof the optical filter 56 of each light-receiving element 50 are set soas to selectively transmit, at maximum, only the light from thecorresponding light-emitting element 30 (the light having one of thepredetermined wavelengths including λ1, λ2 and λ3 as a peak wavelength).

[0108] As these optical filters 56, for instance, the above-mentioneddistributed reflection multilayer film mirror (DBR mirror) may be used.As the DBR mirror is used as the optical filter 56, a narrowerwavelength band can be selected than an optical color filter, thusincreasing resolution in the longitudinal direction of wavelength.

[0109] As the organic EL element 3 a mentioned above, the PIN photodiode5 a of each light-receiving element 50 can also be manufactured by inkjet printing. Specifically, at least one thin film (layer) constitutinga PIN photodiode 5 a can be manufactured by patterning a predeterminedcomposition in the ink jet method and solidifying it as the above-notedorganic EL element 3 a of the device 1. In this case, theabove-described effects by ink jet printing can be obtained.

[0110] Additionally, the thin films constituting the DBR mirror (opticalfilter 56) of each light-emitting element 50 may be also formed by theabove-described liquid-phase film forming method.

[0111] More preferably, each DBR mirror may be manufactured by ink jetprinting as the organic EL element 3 a described above. Specifically,each thin film constituting each DBR mirror is preferably manufacturedby patterning the composition in the ink jet method and solidifying itas the above-noted organic EL element 3 a of the device 1. In this case,the above-described effects by ink jet printing can be obtained.

[0112] As illustrated in FIG. 9, the input side of each correspondingamplifying circuit 60 is connected to the PIN photodiode 5 a of eachlight-receiving element 50 mentioned above.

[0113] Additionally, a predetermined circuit 8 is connected to theoutput side of each amplifying circuit 60, through each correspondingwiring 70.

[0114] The amplifying circuits 60 and the circuit 8 are the same asthose of the above-described device 1, so the explanation of it isomitted.

[0115] This device 10 and the above-mentioned device 1 may be applied toa wide range of integration, including e.g., LSI transistors applyingthe final limit of the 0.18 μm rule to transistor circuits with the 2 to3 μm rule such as TFT. Subsequently, the operation of the device 10 willbe explained.

[0116] The organic EL element 3 a of each light-emitting element 30 isdriven by each of the above-mentioned driving circuits not shown in thefigure, thus emitting light. Specifically, each organic EL element 3 asends (transmits) light signals (light). For a typical case, signaltransmission with the peak wavelength of λ1 will be explained below.

[0117] As shown in FIG. 10, from each light-emitting layer 32 of theorganic EL elements 3 a, light is emitted that has different wavelengthsdepending on the materials and structure of each light-emitting layer32. Each light transmits the transparent electrodes 31 as indicated inthe arrows in FIG. 10, and the band thereof is further narrowed at theoptical filters 35, thus becoming light having the peak wavelength ofλ1, λ2 and λ3 and then being output from the optical filters 35.

[0118] Light having the peak wavelength of λ1 output from thepredetermined optical filter 35 (mentioned as “the light having aparticular wavelength” hereinafter), in other words, light having aparticular wavelength that transmitted the optical filter 35, transmitsthe SiO₂ layer 43 and enters the ITO layer 42. Then, the light isrepeatedly reflected in an interface between the SiO₂ layer 41 and theITO layer 42 as well as an interface between the SiO₂ layer 43 and theITO layer 42, and travels inside the ITO layer 42 toward the PINphotodiode 5 a.

[0119] As illustrated in FIG. 11 and 12, the light having a particularwavelength from the organic EL element 3 a transmits only the opticalfilter 56 of the corresponding light-receiving element 50 as indicatedby the arrows in FIG. 11 and FIG. 12, and enters from thelight-receiving window electrode 51 of the PIN photodiode Sa of thecorresponding light-receiving element 50. In other words, the light isreceived only at the corresponding PIN photodiode 5 a.

[0120] Additionally, from the other two types of light-emitting elements30, light with the peak wavelengths of λ2 and λ3 is emitted,respectively, and are guided to this light-receiving element 50 by thelight-guiding path 4. However, each of both lights is cut off at theoptical filter 56 of this light-receiving element 50 and is notreceived.

[0121] From the PIN photodiode 5 a, the electric current correspondingto the quantity of received light, in other words, electric signals(signals) are output. (Light signals are converted into electric signalsand are then output.) The signals from the PIN photodiode 5 a areamplified at the amplifying circuit 60, and are input to the circuit 8through the wiring 7. The circuit 8 operates based on these signals.

[0122] Additionally, the signal transfer of light with the peakwavelengths of λ2 and λ3 is also the same as above.

[0123] According to this-device 10, like the above-described device 1,heating from the device 10 can be reduced. Moreover, the transfer delayof signals is significantly improved, thus providing a device (circuit)having excellent response properties. Also, the productivity of device10 improves, which is advantageous to mass production.

[0124] Additionally, this device 10 has a plurality of light-emittingelements 30 having different peak wavelengths of light emission and aplurality of light-receiving elements 50 receiving the light (the lighthaving a particular wavelength) from the corresponding light-emittingelements 30, so that a plurality of information may be transmitted atthe same time by using the same light-guiding path 4. (Informationtransmission by multi-channel optical communication using the samelight-guiding path 4 becomes possible.) Accordingly, compared with adevice only with electric wiring, wiring can be simplified.Additionally, compared with a device only having electric wiring, thearea occupied with wiring can be reduced, thereby reducing the size of adevice having the same functions. In other words, the level ofintegration is increased.

[0125] Each light-emitting element 30 and each light-receiving element50 in the device 10 is arranged in line horizontally. However, in thepresent invention, each of them may be arranged in line vertically as inFIG. 9.

[0126] Moreover, the optical filters 35 in the above-noted device 10 andthe optical filters 56 are not limited to the DBR mirror in the presentinvention. Others, for example, optical color filters or the like may beused.

[0127] Furthermore, the light-emitting characteristics (particularly,the peak wavelength of emitted light) of the light-emitting elements 30may be changed by eliminating the optical filters 35 and changing thelight-emitting characteristics (particularly, the peak wavelength ofemitting light) of the light-emitting layers 32 of the organic ELelements 3 a.

[0128] Additionally, in the present invention, the light-emittingcharacteristics (particularly, the peak wavelength of emitted light) ofthe light-emitting layers 32 of the organic EL elements 3 a may bechanged without eliminating the optical filters 35.

[0129]FIG. 13 is a figure (a figure showing the plan arrangement ofmembers), showing an embodiment of a device 100 having a lighttransmission means of the present invention that is used when theabove-described device 1 or 10 is actually built in a semiconductorcircuit such as a LSI circuit and a TFT circuit.

[0130] As shown in the figure, on the same substrate 2, two circuitblocks 81 (A) and 82 (B) are provided (formed). The circuit block 81 hasa light-emitting element 301, a driving circuit 11 for driving thislight-emitting element 301, a light-receiving element 502, and anamplifying element 602. The circuit block 82 has a light-emittingelement 302, a driving circuit 12 for driving this light-emittingelement 302, a light-receiving element 501, and an amplifying element601.

[0131] The light-emitting element 301 is connected to thelight-receiving element 501 so as to transmit light to thelight-receiving element 501 through the light-guiding path 401 providedon the substrate 2. Similarly, the light-emitting element 302 isconnected to the light-receiving element 502 so as to transmit light tothe light-receiving element 502 through the light-guiding path 402provided on the substrate 2.

[0132] This device 100 can convert electric signals to light signalsbetween the circuit block 81 and the circuit block 82 inside, and cansend and receive the signals. Specifically, the light signals sent fromthe circuit block 81 can be received at the circuit block 82.Conversely, the light signals sent from the circuit block 82 can bereceived at the circuit block 81.

[0133] The same substrate materials as those of the device 1 mentionedabove may be used for the substrate 2 of the device 100.

[0134] Additionally, for the light-emitting elements 301 and 302, thelight-receiving elements 501 and 502 and the light-guiding paths 401 and402 of the device 100, the same materials and structures as in theabove-described device 1 may be applied. Moreover, the samemanufacturing processes as those in the above-mentioned device 1 may beapplied.

[0135] Also, the driving circuits 11 and 12 of the device 100 areusually electronic circuits using a bipolar transistor, a MOS-FET, orthe like.

[0136] Furthermore, for the amplifying circuits 601 and 602 of thedevice 100, as in the above-described device 1, the electronic circuitsshown in FIG. 5, FIG. 6, FIG. 7 and FIG. 8 may be used.

[0137] The operation of this device 100 is almost the same as that ofthe above-described device 1. However, the circuit blocks 81 and 82 cancarry out transmission and reception respectively (particularly, inparallel). In other words, the transmission from the circuit block 81 to82 and the transmission from the circuit block 82 to 81 can be carriedout (particularly, in parallel), which is different from the device 1.

[0138] Additionally, in this device 100, as the above-mentioned device1, only one type of light is used as light for generating light signals,but the light is not limited to this. Needless to say, as in the device10 described above, transmission and reception functions using aplurality of lights having different peak wavelengths may be added. Thiscan be achieved by appropriately combining the above-mentioned device100 and the device described above.

[0139] A device having the light transmission means of the presentinvention is applied to a signal transmission device between circuitblocks (between a predetermined circuit block and another circuit block)in one semiconductor chip where a general semiconductor integratedcircuit is used, and signal transfer device between a predeterminedsemiconductor chip and another semiconductor chip, a signal transferdevice between a circuit board on which a semiconductor chip is mountedand a mounted chip, a signal transfer device between the predeterminedcircuit board mentioned above and another circuit board, and so forth.

[0140] Furthermore, a device having the light transmission means of thepresent invention may also be applied to a signal transmission devicebetween TFT circuits (between a predetermined TFT circuit and anotherTFT circuit), and a signal transmission device between a TFT circuit anda general semiconductor circuit.

[0141] A device having the light transmission means of the presentinvention, particularly as the above-mentioned embodiments, isapplicable to the devices sending signals to a flat panel display suchas a liquid crystal display, a plasma display, an organic EL display,and the like.

[0142] Devices having the light transmission means of the presentinvention were explained above based on each embodiment in the figures,but are not limited to these. The structure of each section can beswitched to an optional structure having the same functions.

[0143] For example, in each embodiment mentioned above, light-emittingelements, light-guiding paths and light-receiving elements are providedin a one-dimensional direction but may be provided in a two-dimensionaldirection (provided on a substrate in a two-dimensional direction) inthe present invention.

[0144] Additionally, in the present invention, a light transmissionmeans may have a plurality of light-emitting sections, light-receivingsections and light-guiding paths.

[0145] Furthermore, in the present invention, light-emitting elements,light-guiding paths and light-receiving elements may be provided in athree-dimensional direction. The embodiment thereof will be simplyexplained below based on FIG. 14.

[0146] As illustrated in FIG. 14, this device (semiconductor device) 20is a multilayer device wherein a first layer 20 a, a second layer 20 b,a third layer 20 c, a fourth layer 20 d and a fifth layer 20 e aresuccessively laminated on a substrate 2.

[0147] In this case, the relations between a light-emitting section 213and a light-receiving section 227 in the fifth layer 20 e are the sameas the relations between the light-emitting section and thelight-receiving section of the device 1 and the device 10 mentionedabove.

[0148] Moreover, the relations between the light-emitting section andthe light-receiving section of the device 1 and the device 10 mentionedabove are the same as the relations between a light-emitting section andthe light-receiving section that is connected to the light-emittingsection through a light-guiding path not shown in the figure indifferent layers (in a perpendicular direction relative to the substrate2), which are the relations between a light-emitting section 211 and alight-receiving section 223, the relations between a light-emittingsection 212 and a light-receiving section 221, the relations between alight-emitting section 213 and a light-receiving section 224, and therelations between a light-emitting section 214 and a light-receivingsection 222 and between 225 and 2264.

[0149] It is preferable to manufacture this device 20, for example, asfollows:

[0150] First, the first layer 20 a, the second layer 20 b, the thirdlayer 20 c, the fourth layer 20 d and the fifth layer 20 e is formed oneach predetermined substrate not shown in the figure.

[0151] Subsequently, the first layer 20 a is separated from thesubstrate by a predetermined method, and is transferred onto thesubstrate 2. Similarly, the second layer 20 b, the third layer 20 c, thefourth layer 20 d and the fifth layer 20 e are then separated from thesubstrates and are successively laminated (transferred) while beingaligned in a predetermined method. The method described in Laid-openJapanese Patent Application 10-125930 by the present applicant may beadopted for the detail of this method.

[0152] According to this device 20, the same effects as theabove-mentioned device 1 and device 10 can be obtained. At the sametime, integration may be easily improved.

[0153] Additionally, in the present invention, the number of layersconstituting the device is not limited to five, and may be, forinstance, two to four, or six or more.

[0154] In each embodiment as described above, a light-emitting elementis made of an organic EL element. However, in the present invention, alight-emitting element is not limited to this, and may be formed of, forexample, an organic EL element, a light-emitting diode (LED), asemiconductor laser (laser diode), and the like.

[0155] Moreover, in each embodiment mentioned above, a light-receivingelement is made of a PIN photodiode, but is not limited to this in thepresent invention. A light-receiving element may be formed of, forinstance, various photodiodes such as a PN photodiode and an avalanchephotodiode, a phototransistor, a photoluminescence (organicphotoluminescence), and the like.

[0156] Also, in the present invention, the above-described predeterminedcomponents in each embodiment may be appropriately combined.

[0157] As explained above, according to the device having the lighttransmission means of the present invention, information (signals) istransmitted mainly by optical communication in a device where fineelements are integrated, so that heating from the device can be reducedand the delay of signals can be significantly decreased. Thus, a device(circuit) having excellent response properties can be provided.

[0158] Moreover, when thin films constituting an element are patternedby the ink jet method, fine patterning can be easily, quickly andaccurately carried out. Additionally, a film thickness can be easily andaccurately adjusted by increasing or decreasing the discharge quantityof a composition, so that the properties and the like of a film can beeasily and freely controlled thereby.

[0159] Thus, by the ink jet method, light-emitting and light-receivingelements and a semiconductor element may be easily made hybrid.

[0160] Accordingly, an element having preferable characteristics, sizeand patterns can be easily formed on a substrate (for instance, a Simonocrystal substrate or a substrate where fine elements are integratedsuch as a TFT circuit). Thus, the productivity of devices improves,which is advantageous to mass production.

[0161] Moreover, when a light-emitting section has a plurality oflight-emitting elements having different light-emitting characteristics,a plurality of information may be transmitted at the same time by usingthe same light-guiding path particularly as the light-emitting sectionhas a plurality of light-emitting elements having different peakwavelengths of emitting light. Accordingly, compared with a device withonly electric wiring, wiring can be simplified. Additionally, comparedwith a device with only electric wiring, the area occupied with wiringcan be reduced, and the generation of heat can be inhibited, thusincreasing integration.

22. A device comprising: a light transmission device having alight-emitting section having at least one light-emitting element madeof a thin film, a light-receiving section having at least onelight-receiving element made of a thin film, and a light-guiding paththat guides light from the light-emitting section to the light-receivingsection, wherein the light-emitting section, the light-receivingsection, and the lightguiding path being integrated.
 23. The deviceaccording to claim 22, the light-emitting section, the light-receivingsection and the light-guiding path being arranged in at least aone-dimensional direction.
 24. The device according to claim 22, thelight-emitting section, the light-receiving section and thelight-guiding path being arranged on a same substrate.
 25. The deviceaccording to claim 22, the light-emitting section, the light-receivingsection and the light guiding path being arranged in a two-dimensionaldirection.
 26. The device according to claim 22, the light-emittingsection, the light-receiving section and the light-guiding path beingarranged in a three-dimensional direction.
 27. The device according toclaim 26, further comprising a layer having at least one of thelight-emitting section, the light-receiving section and thelight-guiding path, the layer being laminated.
 28. The device accordingto claim 22, the light-emitting section having a plurality oflight-emitting elements having different light-emitting characteristics.29. The device according to claim 22, the light-emitting section havinga plurality of light-emitting elements having different peak wavelengthsof emitted light.
 30. The device according to claim 28, thelight-receiving section having a plurality of light-receiving elementsthat receive light from corresponding the light-emitting elements. 31.The device according to claim 22, at least one thin film constitutingthe light-emitting element being patterned by an ink jet method.
 32. Thedevice according to claim 22, the light-emitting element being anorganic EL element.
 33. The device according to claim 22, thelight-emitting element being an organic EL element and an opticalfilter.
 34. The device according to claim 33, the optical filter being adistributed reflection multilayer film mirror made of a plurality oflaminated thin films having different refractive indexes.
 35. The deviceaccording to claim 22, at least one thin film constituting thelight-receiving element being patterned by an ink jet method.
 36. Thedevice according to claim 22, the light-receiving element being anorganic element.
 37. The device according to claim 22, thelight-receiving element being an organic element and an optical filter.38. The device according to claim 22, the light-guiding path includingthin films.
 39. The device according to claim 22, at least one thin filmconstituting the light-guiding path being patterned by an ink jetmethod.
 40. The device according to claim 22, further comprising a thinfilm transistor.
 41. The device according to claim 22, furthercomprising a plurality of circuit blocks on a same substrate, each ofthe plurality of circuit blocks comprising the light-emitting sectionand the light-receiving section.
 42. The device according to claim 41, agap between predetermined circuit blocks of the plurality of circuitblocks being connected by the light-guiding path, and signals beingtransmitted and received by light through the light-guiding path betweenthe circuit blocks.